The inventions relate to authentication technology for polymer based articles, particularly to methods of authenticating polymer based articles, methods of facilitating such authentication, and methods of making articles capable of authentication. The invention particularly relates to nondestructive authentication technology for use in data storage media made of polycarbonate such as compact disks (CDs) and digital versatile disks (DVDs).
Data storage media or optical storage media such as CDs and DVDs traditionally contain information such as machine-readable code, audio, video, text, and/or graphics. Data storage media often include one or more substrates made of polymers such as polycarbonate.
A major problem confronting the various makers and users of data storage media is the unauthorized reproduction or copying of information by unauthorized manufacturers, sellers and/or users. Such unauthorized reproduction or duplication of data storage media is often referred to as piracy and can occur in a variety of ways, including consumer level piracy at the point of end use as well as whole sale duplication of data, substrate and anti-piracy information at the commercial level. Regardless of the manner, piracy of data storage media deprives legitimate software and entertainment content providers and original electronic equipment manufacturers significant revenue and profit.
Attempts to stop piracy at the consumer level have included the placement of electronic anti-piracy signals on information carrying substrates along with the information sought to be protected. The machine readers and players of such data storage media are configured to require the identification of such anti-piracy signals prior to allowing access to the desired information. Theoretically, consumer level duplications are unable to reproduce these electronic anti-piracy signals on unauthorized copies and hence result in duplicates and copies that are unusable.
However, numerous technologies to thwart such consumer level anti-piracy technologies have been and continue to be developed. Moreover, commercial level duplications have evolved to the point that unauthorized duplicates now contain the original electronic anti-piracy circuit, code, etc. For example, commercial level duplication methods include pit copying, radio frequency (RF) copying, “bit to bit” copying and other mirror image copying techniques which result in the placement of the anti-piracy signal on the information carrying substrate of the duplicate along with the information sought to be protected. Other technologies commonly used by hackers include the modification of the computer code in order to remove anti-piracy (also referred to as copy-protection or copy-proofing) features and enable unlimited access to the data.
One anti-piracy technology aimed at combating these more sophisticated consumer and commercial level reproduction and copying practices involves the placement of ‘tags’ or authentication markers in substrates used in the construction of data storage media. Such tags or authentication markers can be detected at one or more points along the data storage media manufacturing or distribution chain or by the end use reader or player used to access the data on a particular CD or DVD.
For example, in Cyr et al., U.S. Pat. No. 6,099,930, tagging materials are placed in materials such as digital compact discs. A near-infrared fluorophore is incorporated into the compact disc via coating, admixing, blending or copolymerization. Fluorescence is detectable when the fluorophore is exposed to electromagnetic radiation having a wavelength ranging from 670 to 1100 nanometers.
Hubbard et al., U.S. Pat. No. 6,514,617 discloses a polymer comprising a tagging material wherein the tagging material comprises an organic fluorophore dye, an inorganic fluorophore, an organometallic fluorophore, a semi-conducting luminescent nanoparticle, or combination thereof, wherein the tagging material has a temperature stability of at least about 350 degrees C. and is present in a sufficient quantity such that the tagging material is detectable via a spectrofluorometer at an excitation wavelength from about 100 nanometers to about 1100 nanometers.
WO 00/14736 relies on one or more intrinsic physical or chemical characteristics of the substrate materials to distinguish unauthorized duplications of information-carrying substrates. Such anti-piracy characteristics may be based on performance characteristics such as (for example in the case of an optical disc) the weight and/or density of the disc; the spin rate of the disc; the acceleration and deceleration of the disc; the inertia of the disc; the spectral characteristics such as reflectance of the disc; the optical characteristics such as light transmittance of the disc; the water absorption and dimensional stability of the disc; the data transfer rate of the disc; and the degree of wobble of the disc, or combinations of such characteristics.
Catarineu Guillén, U.S. Pat. No. 6,296,911 discloses a method for obtaining the chromatic variation of objects in response to external stimuli, the method comprising the incorporation in the desired objects of various pigments having combined effects comprising a luminescent pigment, a thermochromic pigment permitting the change in the color according to the temperature and/or a hygroscopic pigment that will provoke a variation in the chromatic characteristics according to humidity.
U.S. Pat. No. 5,329,127 discloses a method of identifying different plastics, wherein each plastic is provided with a plurality of fluorescence dyes which differ in terms of their emission frequencies and/or in terms of the duration of their fluorescence, so that a fluorescence pattern, which is distinguished by the duration of the fluorescence and/or by the frequencies occurring, can unambiguously be assigned to each plastic.
However, the ability of unauthorized manufacturers, sellers, and/or users of data storage media to circumvent such practices continues to grow with increasingly sophisticated practices. For example, unauthorized manufacturers of data storage media are known to illegally obtain legitimately manufactured-tagged substrates for the purposes of making unauthorized reproductions. Moreover, the high profitability of piracy has enabled some unauthorized manufacturers and their suppliers to reverse engineer tagged substrate materials for the purpose of identifying previously unknown tags and producing similarly tagged data media storage substrate.
There is therefore a need to find methods of tagging and authenticating data storage media substrates that are currently unknown and/or unavailable to unauthorized manufacturers, sellers, and/or users of data storage media. In particular, it would be desirable to find authentication markers or combinations of authentication markers for use in data storage media substrates that are difficult to obtain, reproduce, use, and/or find for the purposes of authenticating data storage media substrates and data storage media.